tests: Remove unused file

test_updater_ng.py is a little archaic (as it uses the static test
repository content from ye olden days). This commit does not change that
but removes an extra file in client cache dir: it is now quite confusing
as it looks a bit like intermediate root caching but is just an unused
file.

This has the nice side effect that tests now longer need to workaround
this extra file.

Signed-off-by: Jussi Kukkonen <jkukkonen@google.com>

Author: jku

tests/repository_data/client/test_repository1/metadata/current/1.root.json

@@ -161,7 +161,6 @@ def test_refresh_and_download(self) -> None:
         # top-level targets are already in local cache (but remove others)
         os.remove(os.path.join(self.client_directory, "role1.json"))
         os.remove(os.path.join(self.client_directory, "role2.json"))
-        os.remove(os.path.join(self.client_directory, "1.root.json"))
 
         # top-level metadata is in local directory already
         self.updater.refresh()
@@ -208,7 +207,6 @@ def test_refresh_with_only_local_root(self) -> None:
         os.remove(os.path.join(self.client_directory, "targets.json"))
         os.remove(os.path.join(self.client_directory, "role1.json"))
         os.remove(os.path.join(self.client_directory, "role2.json"))
-        os.remove(os.path.join(self.client_directory, "1.root.json"))
         self._assert_files([Root.type])
 
         self.updater.refresh()
@@ -233,7 +231,6 @@ def test_implicit_refresh_with_only_local_root(self) -> None:
         os.remove(os.path.join(self.client_directory, "targets.json"))
         os.remove(os.path.join(self.client_directory, "role1.json"))
         os.remove(os.path.join(self.client_directory, "role2.json"))
-        os.remove(os.path.join(self.client_directory, "1.root.json"))
         self._assert_files(["root"])
 
         # Get targetinfo for 'file3.txt' listed in the delegated role1